Revise labels for new Node.js Release Schedule

[shadowspawn]

The Node.js release schedule is changing. The announcement is:

• https://nodejs-org-git-fork-ulisesgascon-release-announcement-openjs.vercel.app/en/blog/announcements/evolving-the-nodejs-release-schedule

Old Node.js terminology (https://nodejs.org/en/about/previous-releases):

• even: current / active LTS / maintenance LTS
• odd: current / maintenance

New terminology used in announcement:

• alpha / interim / LTS

I think this makes the little used node support labels somewhat obsolete (like lts_active), and current is not mentioned. lts_latest got used in some training material and will retain that as an alias even if do not document. Likewise, stable.

Not sure if n users will want to target the latest version after it reaches alpha? n uses the index information from https://github.com/nodejs/nodejs-dist-indexer and does not do date calculations. I am watching that repo to see if alpha/interim get added to the index.